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Our recent Stunning Interiors roundup got a lot of people talking about interior rendering tutorials, and today we're happy to bring in Flavius Cristea to finish discussing his process when creating stunning interior renders using 3Ds Max. With the modelling mostly done, today's tutorial looks at material creation and the final rendering process, and is a great insight into the art of Arch-Vis Interiors.
Additional Files/ Plugins:
Open your scene from the first part of this tutorial, we'll carry on from there. As you notice in the final image above, I've added a candle and a coaster under the wine glass using very basic modeling as you can see in the image below. The techniques are the ones you've learnt from the previous part.
Set V-ray as your main render engine. We are going to set some test render settings. Go to the V-ray tab and change the settings to those seen below, and then enable the V-ray Frame Buffer.
Info: The Adaptive DMC Image Sampler is what you'll use 95% of the time if you're a V-ray user. Here, we've also changed the Color Mapping type from Linear to Rheinhard which is actually a blend between Linear and HSV exponential. Now V-ray is hell of a renderer; it's quite complex with a lot of options and I can't explain every single of them here. While I will comment on some of the things I've changed, I can highly recommend this online V-ray Help site. It's the best free source I know so far : http://www.spot3d.com/vray/help/150SP1/index.htm .
Note: Just before we begin, make sure you know how to see the maps in the viewport, by toggling on the Show map in viewport option shown below.
Go to the Indirect Illumination tab. Turn on GIIrradiance map and Light cache map values to those shown below.
Info: You can make your own presets with these values. A Very Low preset as shown here would be set with one purpose in mind: fast render times. Make sure you check Show calc.phase on, especially for the light cache, as you'll get immediate results while this map is computing, and sometimes this is enough for you to adjust the ligtning or colors etc without having to wait for the final image to render.
Step 4 - The Walls
Because by now you should already have an idea of the color of the the walls, there is no point in making test renders with gray walls. Select the walls and isolate them by hitting ALT +Q. Select the two polygons shown. In the Editable poly options for the object, scroll down until you find Polygon:Material ID's. Where it says Set ID, input 2 and hit Enter. Press CTRL+I to invert the selection and select all the other polygons .In the Set ID, input 1 and hit Enter.
Info: You have assigned a group of polygons to a specific ID ( 1 and 2 ) . These ID's work in conjunction with the Multi/Sub-Object material which we'll use later.
Tip: Isolate your object when assigning materials, so that you can easily rotate around them to see if everything is ok.
Open the Material Editor (press M ). Pick the first color slot and click the Standard button. Choose Multi/Sub-Object. Set the number of materials to 2. Click on the first material (it says White(VrayMtl) in the screenshot below and will say Standard in your editor) and select a Vray Material. Set the Diffuse color to an off white (RGB: 250;250;250). Click on Go to parent to go back to the Multi/Sub-Object Material. Click on the second material (it says 7 in the screenshot below), and again select a V-ray Material. Set the Diffuse to RGB 106;44;63, and when done, drag and drop the entire Multi/Sub-Object material onto the walls material (the material I've highlighted in cyan).
Step 6 - The Ceiling
Unhide the ceiling and drag the white material from our Multimaterial on it. Be very careful to drag the button as I show in the picture below. If you were to be inside the white material and drag it, it would not work correctly, and 3Ds Max would assign the entire Multi/Sub-object material to the ceiling- something you don't want!
Tip: Remember this way of assigning independent materials from a Multi/Sub-object one because it's a technique we'll use quite often throughout this tutorial.
Step 7 - The Floor
Select the floor and isolate it. Add a UVW modifier, set it to Planar and check Real world map size. Assign a new VrayMtl to the floor. and set the Refl. glossiness to 0.78. Now put the wood-01_d wood texture in the diffuse Bitmap slot. Again, check Use Real-World Scale and set the Width and Height to 700 cm.
Info: You need to tell 3ds max how to put a texture( non procedural of course ) on an object. This is where UVW mapping comes in. Since real-world scale was being used, you had to also check that in the UVW settings. I know that in the real-world, my texture would be around 700 cm by 700 cm, so that's why that value has been used.
In the Reflection slot put a Fallof map. Inside the Front slot ( Map#8 in the screenshot below) put your reflection map (wood-01_r) and use the exact same UV Coordinate settings as for the diffuse map (700 cm by 700 cm and check Real world scale). Now go back to the parent (once) and put the exact same map with the same settings in the Side slot, but in the Output tab click Invert. Now go back to the Fallof map settings and set the Side map Percentage (highlighted in pink in the screenshot) to 40. In the Bump map slot, add in your bump map and use exactly the same settings as with the other maps above. Set the Bump value from the default of 30 to 10.
Info: You could have just put the reflection map in the reflection slot but the results wouldn't be overly realistic. Here you have used a falloff map instead, which changes the reflection based upon the two maps used. This is how it works: If you were to look straight down at the floor, only map#8 (the front one) would be active. The more you tilt your head however, the more the front map would blend with the side one. Finally, if you were to look almost parallel to the floor, only the side map would be active, and only at the percentage value set (in our case 40%) - the rest would be represented by black, meaning no reflection. To find these values I actually studied my own floor! Try it! Look at your floor and change your viewing angle to see how the refleciton changes. I should point out that pure white reflects 100% and pure black reflects 0% - the greys are in between. Finally the Glossiness was adjusted to 0.78 to blur the reflection.
Note: The 0.78 value and the 40% value for the side slot map were obtained by trial and error after completing several test renders.
Step 9 - The Window
Make a new V-ray Mtl and name it Windows (I won't say this every time, but it's very useful to name your materials!) Change the Diffuse color to almost black (RGB:8,8,8) and the Reflection color to RGB:133,133,133. Check on Fresnel reflection and set the Refl.Glossiness to 0.94. Assign this material to the window frame. Now create another Vray Material with a Diffuse color of 0,0,0, and a Reflection and Refraction color of around 250,250,250. Turn on Fresnel reflections and set the Fog color to a very, very pale green - I used RGB :243,247,245. Set the Fog multiplier to 0.2 and check Affect shadows. Assign this material to the actual glass.
Info: The window frame material is as basic as it can get.The glass is also very simple, but be careful when using Fog color. Vray is, in my opinion, way too sensitive, and you have to use really, really pale colors and low multiplier values. Checking Affect Shadows is not so important in this scene, because there is no light coming from the outside. But if for instance you had sunlight in your scene, this would allow you to get more realistic, opaque shadows from the glass.
Step 10 - The Lights
Hide everything except the walls and the floor. Now place 3 V-ray area lights as you can see in the picture below. The 3rd Area light is at 100 cm above the ground. The second one almost touches the floor and the first one is at 232 cm on Z.
Step 11 - Light & Camera Settings
Set the settings for the Vray lights as shown in the screenshot below. The orange colour used for Light 1 and 2 is RGB 253,106,10 and the yellow color from the 3rd one is RGB. Use the settings in Vray cam for both of the V-ray physical cameras.
Info: A lot of things have been done here to set up the final lighting. The important thing is not really the settings themselves, but how I chose them. I must admit, I've only ended up with these values after spending a whole day test rendering, both with a completely empty room, and with the room full of furniture. The orange color was used to give the room a very cozy and warm feeling - it is a bedroom after all - and it matches the picture I had in mind (remember what I said about concept & interior design ideas in the introduction of this tutorial). We don't need the light to affect the reflections in our scene (we'll use something else for that), but placement is still very important.
If you take a look at the render below, (one of my initial test renders) you can probably spot many problems. First of all there is not enough lightning in the scene, and the room is way too dark (and quite boring!) There is no feeling of warmth and the image completely lacks emphasis - the big dark panel behind the bed didn't particularly help me either.
Info: The Vray camera settings work exactly as they would in the real world.The ISO was changed to 500 and f-number to 5.0 to let more light to pass into the camera. I also turned off vignetting, as it's ten times easier to do this in Photoshop where you have full control over the look. I also left the white balance at neutral.
Step 12 - The First preview
First of all, make sure you unhide the ceiling before rendering! Now go into your Vray camera view, press F10 and hit enter to render out. You should get a result very similar to what you see below. Click on the two little buttons Use color curves correction and Use exposure correction. Set the slider indicated by the green arrow to around +0.50.
Info: The Vray frame buffer is a brilliant little thing. Your rendered image is in 32 bits color space (what we call a HDR image) so you can adjust the exposure without re-rendering by using the Exposure Correction (if you were to change the f-number or the iso however, you would have to re-render). The curves act exactly like the curves in Photoshop. My usual workflow is to try to get a decent render by changing the F-number and ISO values initially, and then make minor adjustments in the V-ray Frame Buffer. And yes, the image is a bit dark at the moment - the lighting isn't quite finished just yet!
Step 13 - The Wall light
Create a thin box and place it in the inner extrusion you made inside the wall. Then create a new VrayLightMtl and set the Color Multiplier to 17.Assign this material to the box.
Info:VrayLightMtl is actually a self illuminated material. You had to use a multipler of 17 so that it looked the correct brightness to the V-ray Physical Camera. Make another test render and you should see the difference! The image now has much more contrast and emphasis in it. You can also see the bump mapping on the floor much more clearly.
Step 14 - The Curtains
Unhide the curtains. Apply a UVW Mapping modifier to each of the two curtain parts, but don't check the Flip option just yet (wait until the next step!) Adjust the Reflection Glossines to 0.65 and the Reflection Color to around RGB:15,15,15.
Info: We are going for a silk-like material here, so we had to make it a little reflective and extremely blurry, which explains the 0.65 Glossiness value for reflection and the 0.95 for refraction.
Inside the curtain material, scroll down until you find Maps. In the Diffuse slot put a Falloff map inside of which you should put the maps indicated in the picture below. In the Refraction slot, put the same falloff map, but with a clear side slot.
Info: If you look directly at a silk surface, you should notice that it looks lighter than if you look at it at an angle, which is why we use a lighter map in the front slot and a darker one in the side slot. The same principle applies to refraction but since we've only used a 15% multiplier the influence is minimal - but still observable to the trained eye! As you can see in the image below, the white parts of the curtains are closest to the window, so you'll need to flip one of the UVW maps. Why bother? Interior design principle! It makes the overall image a bit more balanced and looks a little more composed. With that done, feel free to make another test render if you wish.
Step 16 - The Bed
Unhide the bed and isolate the selection for better workflow. Create a new Vray Material. Add the wood_diff map in the Diffuse slot, the wood_refl in the Reflection slot, and the wood_b map in the Bump map slot. Set the Refl.Glossiness to 0.67 and check Fresnel Reflection. Click the little L button to unlock the Fresnel IOR and set it from 1.6 to 1.8 . Now assign this material to one of the wooden bed pieces. Assign a UWV modifier to this piece and set it to Box. Select the gizmo for the modifier, and scale it until the size of the grain looks correct. Repeat this step for each individual piece of the bed.
Info: Be sure to apply the UVW map to each individual bed piece, so it will look like there are random wooden textures on all of the parts. Also, make sure you rotate the gizmo so that the wood fibres aren't running in the same direction (look at the arrows from the below image to see the directions I used). We've unlocked the Fresnel IOR in order to put in a higher value, making the wood just a little bit more reflective.
Step 17 - The blanket and pillows
Select the blanket and each pillow and add a UVW map modifier to each object. Set it to Box, and click the Fit button. Now create a new Vray Material. Assign it to the blanket and to the small pillows. In the Diffuse slot, put the linii.jpg map (just something I quickly drew with the brush tool in illustrator). Put a Speckle Map in the Displacement slot using the values shown below, and a Multiplier value of about 1.5.
Info: The quality of this material is 95% down to the amazing V-ray displacement. If you want to draw your own lines map please feel free, just make sure that the ratio of the texture is the similar to the blanket's one. Also feel free to adjust the tiling values as you wish. Finally adjust the Gizmos for the small pillow UVW maps in the same manner as you did with the wood bed texture to make sure that the don't all look exactly the same! You can use the Show map in Viewport option to make this process easier.
Make a copy of the blanket material and rename it to pillow. Clear the Diffuse slot, and assign this material to the larger pillows.
Step 19 - Chrome
Create a new VrayMtl and set the values as shown below. Then set the Refl.Glossiness to 0.6, and assign this material to the bedside legs.
Step 20 - Lamp
We don't need to create any new materials for this one, as it just uses the wood from the bed and the VrayLightMaterial. Apply a UVW map to each wooden piece and adjust the gizmo until it looks correct.
Step 21 - The Soft Armchairs
You don't even need a UVW map for this one, because the Speckle map is procedural. Apply the same material you have used for the large pillows.
Step 22 - The Decorative vase
Make a new Vray Material. Set the Diffuse color to a pale beige, the Reflection color to around RGB 133,133,133, and turn on Fresnel Reflections. Now set the Refl.Glossiness to 0.94, and assign this material to one of the vases. Then make a copy of the material, rename it, set the diffuse color to just off black (eg. RGB 8,8,8) and assign it to the other vase.
Step 23 - The Small Table
Assign the existing materials as shown.
Step 24 - The Candle
Make a new Vray Mtl. Set the Reflection color to RGB 10,10,10 and the Refl. Glossiness to around 0.85. In the Diffuse slot add a Gradient Ramp Map and use the RGB values indicated on the image below. Finally change the W Angle to -90 and apply to the candle object.
Create a Vray area light, set it to Spherical with a radius of approximately 3.8, and position it as you can see in the picture below.
Info: This Light will be used to simulate the candle flame. The Multiplier is set to 30, which is quite high and will completely blow-out the plane the candle flame object. This technique is not suitable for a close up shot, but works really well if you position the camera a few feet away! Make sure you check Affect Reflections this time.
Step 26 - The Wine Glass
Assign the existing glass material to the actual glass. For the liquid, make a new material, set the Diffuse color to black and the Reflection color to a pale grey. Now turn on Fresnel reflections, and add a Falloff map with the values shown into the Refraction slot. Set the IOR to 1.333, the Fog color to a strong red (approx RGB 196,0,0) and the Fog multiplier to around 0.05.
Tip: 1.333 is the index of refraction (IOR) of water. The falloff map here was used to make sure that the liquid is more opaque through the middle and more transparent on the sides nearer the glass.
Step 27 - The Coaster
A very basic material! Just a diffuse texture and a bump map (which is actually a desaturated version of the diffuse texture!) Since this is a small object, and really quite far away from the camera, I won't spent much time on this material.
Tip: Don't take this as being lazy! Being time efficient and using less RAM is very often as important as your ability to make things look great!
Step 28 - A Reflection trick
Make a box large box as shown, position it in the back of the room and assign the Vray Light material to it.
Info: In my test renders, I noticed that the decorative vases and the wine glass were too washed out, because there was nothing for them to reflect. My solution? Make a lightbox! You can make the box invisible to the camera and visible only to reflections if you'd like. The red lines on the image show exactly how the lightbox reflects in the vases.
Step 29 - The Carpet
Go into your top view and, using the line tool, make a shape similar to the one you see below. With that done, convert it to an Editable poly, Extrude the polygons with a value of approximately 2.5 cm, scale the top polygons in slightly, and finally add a Turbosmooth modifier with Iterations set to 2.
Info: This object will act as the base for our Vray Fur.
Position the carpet object as seen below and then go to your Create panel and select Vray. Click on Vray Fur once.
Select the VrayFur and the carpet object, and assign a new material to them both. Change the Diffuse color to approximately RGB:106,44,63, and adjust the VrayFur parameters as shown below.
Info: Make sure the Source object for the VrayFur is set to your carpet object. As always, I reached all of the values shown by isolating the carpet object and making many test renders!
Step 32 - The Final Render Settings.
Enter the Render Settings and make sure you have the Vray frame buffer enabled (under the Vray :: Frame buffer rollout). Now go to Render elements and add the passes shown. Finally choose a suitable image Resolution in the Common tab, select the Camera and render!
Info:If you think the reflections (on the floor especially) are a bit noisy, try increasing the Min. samples (surrounded with a black border in the bottom left of the image below) from 8, to 16 or 32.
Step 33 - Final Render (no post processing)
Hopefully your final render looks something similar to this! Now adjust the exposure correction to +0.53 and adjust the curves to your liking. Finally save both the main 'beauty' pass (shown here), and the alpha pass.
Step 34 - Ambient Occlusion Pass
Before setting up the scene for the Amb Occ pass, first save your scene, and then save an alternate version of it - with amboccpassor something similar in the name. We're going to be deleting some of our work here, so it's always a good idea to have backups!
First delete all of the Vray area lights, and the Vray Fur object. Then assign Mental Ray as the renderer, and set the Environment Color to white. Create a new Mental Ray material and put an Ambient/Reflective Occlusion map into the surface slot as shown.
Inside the Ambient/Reflective Occlusion map settings, change the Samples to 128 and the Max Distance to 30 cm. Now go back to Mental Ray parent material and drag & drop it in the Material Override slot. This material will now be used for all of the objects in the scene.
Render! This is how your ambient occlussion map should look. If you're happy, save it out.
Step 37 - Post Processing
Open your beauty pass, alpha pass and ambient occlusion pass in Photoshop. Also look for an image you can place outside the window and import that too - I used a night shot of a city. Hit Ctrl-A, Ctrl-C to select all and copy that outside image, select your main beauty render, and hit Ctrl-P to paste it into a new layer. Then add a layer mask to it using the button shown.
Now go to your Alpha map and select all/copy using the same technique. Back in the beauty pass, hold down Alt and click once on the thumbnail of the mask we just created. Our beauty pass should turn entirely white but don't panic! We're seeing the alpha channel and our beauty pass is only a click away. Now press Ctrl+V to paste our alpha pass into the alpha channel. Press Ctrl+I to invert the map, and then click on the Unlink the mask to the layer button once.
Info: We've unlinked the mask from the layer so that we can freely move the nightshot render around without moving the alpha map. The alpha map was inverted because we only need the window area to be affected (white).
Press Ctrl+T to free transform the nightshot photo. Make it smaller until the size/proportion looks right (as shown below) and then move it into place outside the window. Change the layer blending mode to Soft Light which will make it slightly less intense. You will notice that the photo is not big enough to cover the entire window, so take a soft brush, and, making sure you have the colour layer selected and NOT the alpha layer, paint black above the city until it covers the entirety of the window.
Copy the ambient occlussion pass into the main file using the same select all/copy technique as before. Set it's blending mode to Multiply and set the Fill to 60%. Now take the brush tool (with size around 50 px and a hardness of 0% ) and paint the area indicated on the image below pure white.
Info: Why are we doing this? Well we have a huge area lamp in that portion of the image, so there would be no occlusion happening! Mental Ray calculated occlusion there as it cannot read Vray Light Materials.
Now make a duplicate of your beauty pass (you can drag and drop the layer onto the new layer button to make a copy of it, as shown below). Move the newly duplicated image to the top of the layer stack, and desaturate it by hitting Ctrl+Shift+U.
With the desaturated beauty pass still selected, press Ctrl+L to bring up the Levels command. Move the sliders as you can see below. This is to isolate the brightest parts of our image only. Hit Ok.
Now set the layer blending mode to Linear Dodge. Apply a Gaussian Blur and experiment with different values to alter how far the glow from the light spreads - I used a value of 27 pixels. Press ok when you're happy. Now you can adjust the Fill value to slightly tone down the glow! I used a value of 36% but feel free to experiment!
Finally, add a Levels adjustment layer to the top of the stack and change it's midpoint value to 0.81. This will give the image a little bit more contrast.
Finally, we're done! I would like to point out one main thing, however : don't take any the values above as a rule. Experiment! For example, I've blurred the desaturated image 27px to get the final glow effect. Maybe you could try it with 10 px of blur, or with 35 px just to see what it does. Don't worry if you spend a whole evening adjusting one single material setting, it's that attention to details that matters in the final render. When you've completed your image, study it and try to find 5 things you can improve. It's the best way to learn!
I hope it's been a helpful tutorial, and feel free to post comments here - I'll do my best to reply. If you get stuck with any of the steps above, just yell and I'll explain that specific step in more detail if necessary! Best of luck in all!